The present invention relates to an absorption refrigerating apparatus having two stage evaporators and two stage absorbers, and more particularly to a two-stage absorption refrigerating apparatus suitable for cases in which cold water flows through the two stage evaporators in series.
An example of two-stage absorption refrigerating apparatus having two evaporators and two absorbers wherein cooling water, after cooling a solution in one of the absorbers, cools a solution in the other absorber is disclosed in JP-A-10-300257 specification. Also, examples of two-stage absorption refrigerating apparatus in which a refrigerant sprayed in one of the evaporators is sprayed in the other evaporator and, similarly, a solution sprayed in one of the absorbers is sprayed in the other absorber are described in JP-A-10-160276, JP-A-10-160277 and JP-A-10-160278 specifications.
Among these prior arts, in the refrigerating apparatus disclosed in JP-A-10-300257 specification, in order to simplify a medium circulating circuit for thermally transferring cold generated by the evaporators to a cold-using unit such as an indoor heat exchanger of an air conditioner and thereby enhancing the refrigerating performance of the refrigerating apparatus, a non-azeotropic mixed refrigerant consisting of a plurality of kinds of refrigerants having different boiling points is used as heat-carrying medium circulating between the evaporators of the refrigerating apparatus and the cold-using units. The apparatus has a plurality of absorbers and evaporators to have the non-azeotropic mixed refrigerant evaporated or absorbed in multiple stages.
According to JP-A-10-160276, JP-A-10-160277 and JP-A-10-160278 specifications, in order to increase the utilization rate of exhaust heat in cogeneration systems and thereby reduce the consumption of highergrade fuel, a reducing valve and a heat exchanger for a heat source are provided between a low-temperature solution heat exchanger and a low-temperature generator of a weak solution line, so that the utilization rate of exhaust heat can be increased through exchanges between sensible heat and latent heat. The evaporators and absorbers are divided into a plurality of stages to reduce the concentration of the weak solution line to cause sensible heat and latent heat to be exchanged and thereby to reduce the return temperature of the exhaust heat line.
Incidentally, in an absorption refrigerating apparatus, various elements constituting the apparatus are operated in a vacuum ambiance. For this reason, if any air comes in from outside on account of any factors during operation, or if the absorption solution, water or the like slightly reacts with wall faces of a drum and many heat transfer pipes arranged within the apparatus to generate uncondensed gas, the degree of vacuum of the refrigerating cycle formed within the refrigerating apparatus will be deteriorated.
Since a deterioration in the degree of vacuum results a drop in refrigerating efficiency, it is necessary to discharge outside without delay the air and uncondensed gas, which do not contribute to evaporation or absorption. None of the above described patent applications contains any mention of bleeding the air or uncondensed gas from the refrigerant flow or the solution flow. In particular, where the absorbers are provided in two stages in order to take out cold of necessary temperature or to accomplish efficient exchange of sensible heat and latent heat, since the two stages of absorbers are partitioned from each other, sufficient bleeding of uncondensed gas is impossible if only one stage of absorber is provided with a bleeder.
The present invention is made in view of the technical inadequacies of the above-described prior arts and an object of the invention is to enhance the absorbing capacity of an absorption refrigerating apparatus having a low-pressure absorber and a high-pressure absorber by extracting uncondensed gas. Another object of the invention is to make it possible in a simple configuration to discharge uncondensed gas collected in absorbers out of a two-stage absorption refrigerating apparatus. The invention can attain its purpose if either of these objects is attained.
In order to attain the objects, according to a first aspect of the present invention, there is provided a two-stage absorption refrigerating apparatus including: a high-temperature generator; a low-temperature generator; a condenser; a low-pressure absorber; a low-pressure evaporator; a high-pressure absorber; and a high-pressure evaporator, in which the low-pressure absorber is provided with first bleeding means for bleeding the uncondensed gas in the low-pressure absorber and the high-pressure absorber is provided with second bleeding means for bleeding the uncondensed gas in the high-pressure absorber.
In the two-stage absorption refrigerating apparatus according to the first aspect of the invention, the high-pressure absorber may be arranged underneath the low-pressure absorber and the high-pressure evaporator may be arranged underneath the low-pressure evaporator; the first bleeding means and the second bleeding means may be supplied with the absorption solution from a single pump; the uncondensed gas extracted by the first bleeding means may be led to the high-pressure absorber; confluent means for combining the uncondensed gas extracted by the first bleeding means with the uncondensed gas extracted by the second bleeding means may be provided; and the low-pressure absorber, the low-pressure evaporator, the high-pressure absorber and the high-pressure evaporator may be configured into an integrated drum.
Also in the two-stage absorption refrigerating apparatus according to the first aspect of the invention, the high-pressure absorber may be arranged underneath the low-pressure absorber and the high-pressure evaporator may be arranged underneath the low-pressure evaporator; the first bleeding means may be provided with first pumping means for supplying the absorption solution and the second bleeding means may be provided with second pumping means for supplying the absorption solution; and the uncondensed gas extracted by the first bleeding means may be led to the high-pressure absorber.
Further, the first bleeding means may be provided on a side or near the bottom of the low-pressure absorber and the second bleeding means may be provided at the bottom of the high-pressure absorber; at least one of the first bleeding means and the second bleeding means may be ejector or liquid jet type bleeding means; a communicating pipe for leading the gas in the high-pressure absorber to the low-pressure absorber may be provided on a side of the high-pressure absorber; and piping means for leading the uncondensed gas extracted by the first bleeding means to the vicinity of the second bleeding means may be provided.
In order to attain the objects, according to a second aspect of the present invention, there is provided a two-stage absorption refrigerating apparatus, in which the apparatus includes: a high-temperature generator; a low-temperature generator; a condenser; a low-pressure absorber; a low-pressure evaporator; a high-pressure absorber; and a high-pressure evaporator, and water is used as refrigerant and an aqueous solution of lithium bromide is used as absorption solution, in which the low-pressure absorber is provided with first bleeding means for extracting uncondensed gas within the low-pressure absorber; the high-pressure absorber is provided with second bleeding means for extracting uncondensed gas within the high-pressure absorber; the condenser is provided with third bleeding means for extracting uncondensed gas within the condenser, a pump for supplying the solution to these bleeding means, a gas-liquid separator for separating the uncondensed gas extracted by these bleeding means from the solution, and a gas storage tank for storing the uncondensed gas separated from the solution are provided; and the uncondensed gas extracted by the first bleeding means and the second bleeding means is fed together with the solution by the pump to the high-temperature generator and the low-temperature generator, and thereafter it is fed together with refrigerant vapor generated by the high-temperature generator and the low-temperature generator to the condenser, and the uncondensed gas is extracted by the third bleeding means in the condenser, and the bled uncondensed gas is fed together with the solution to the gas-liquid separator, and is separated from the solution by the gas-liquid separator, and is accommodated into the gas storage tank.
The gas storage tank is provided with pressure gauging means, and an ejector is connected through a valve, and the valve is opened when the pressure detected by the pressure gauging means surpasses a predetermined level, and the uncondensed gas within the gas storage tank is discharged outside by means of the ejector. It is preferable to arrange the gas storage tank in the uppermost part of this two-stage absorption refrigerating apparatus.